An Internet Protocol (IP) telephone system such as Skype is well known in the art. The IP telephone system can be used by installing a telephone application on a personal computer, telephone terminal, or the like. The telephone application is software developed by the IP telephone provider for originating and receiving calls and for implementing voice communications. The telephone application registers a user ID, display name, and profile of a user in order to provide details on the user using the IP telephone.
In recent years, computer operating systems have employed a multi-user environment capable of running a plurality of user environments in parallel. With this operating system, software such as a communication application can run continuously in each user environment independent of each other. One example of such an operating system is Microsoft's Windows XP (registered trademark). In Windows XP, while a user is logged onto Windows (registered trademark), another user may also log on without the first user logging off. Accordingly, software can continue to run in each user environment.
Japanese unexamined patent application publication No. 2005-175722 describes an IP phone system including a personal computer capable of communicating with a network, and a handset that can be connected to the computer with a USB cable. In this system, the person using the handset may make an IP telephone call to another user of a remote device on the network through a telephone application installed on the personal computer.